Major League Baseball on Wednesday released its tentative 2013 master schedule, which includes the Astros' shift to the American League West that will lead to at least one Interleague game every day, and features 19 divisional games for every club and the World Baseball Classic during Spring Training.

There is dramatic change, and yet there are familiar twists. The ESPN "Sunday Night Baseball" opener returns on March 31, featuring teams to be determined. That will be followed by 12 Opening Day games on April 1, including the traditional opener in Cincinnati, where for the first time the Reds will open against an American League team, the Angels.

The regular season will conclude on Sunday, Sept. 29, after back-to-back years of finishing on a Wednesday. That will be five days earlier than the scheduled 2012 conclusion, allowing for more flexibility in postseason scheduling.

The Astros competed in the National League for the first 50 years of their franchise existence, and their move from the NL Central means there will be 15 teams in both leagues and five teams in all six divisions for the first time. Houston kicks off its inaugural AL season with 15 consecutive games against its new division opponents, including an opening series at home against new rival Texas on April 2-4.

That balancing act leads to some significant changes:

• Clubs play 19 games against divisional opponents, for 76 division games total. The 19 games will be played in six series: three at home and three on the road. This playing load, in sharp contrast to past scheduling, will make division races more balanced and competitive. In 2012, for instance, the Pirates do not meet each NL Central foe an equal number of times, and play just 15 games against the Cardinals.

• Each club will play either six or seven games against non-divisional league opponents. Those games will be played in two series: one at home and one on the road. Overall, 66 games will be played against non-divisional league opponents.

• Each club will play 20 Interleague games throughout the season. Those games will be played in eight series: four at home and four on the road. Interleague series featuring prime rivals will include back-to-back two-game series spanning both cities/venues. The week featuring Interleague Play's prime rivals will begin on Monday, May 27, with the host clubs in the same matchups shifting on Wednesday, May 29.

On May 24, Marlins manager Ozzie Guillen will return to Chicago to face the White Sox for the first time. He played 13 seasons for the White Sox and managed them for eight seasons, including a World Series title in 2005.

Former Yankees fixture Don Mattingly will lead his Dodgers against the Bronx Bombers next year in New York (June 18-19) and at home (July 30-31) for Interleague Play. It will mark the first visit to Yankee Stadium for the Dodgers since they moved west in 1958.

Speaking of the Dodgers, they open their season with a three-game series at home against the rival Giants starting on April 1. For further intrigue, Boston visits Los Angeles on Aug. 23-25 for the first time since 2002. Four significant former Red Sox are under contract with the Dodgers for next season: Adrian Gonzalez, Carl Crawford, Josh Beckett and Nick Punto.

The Red Sox will open their season at Yankee Stadium on April 1-3, the first time they have done so since 2005 at the old park. The Yankees opened at Fenway in '10.

There will be some interesting firsts. Evan Longoria and the Rays go to Dodger Stadium for the first time on Aug. 9-11. The Cubs visit Oakland for the first time on July 2, so the Coliseum will represent the 114th different ballpark they have visited in franchise history. Marlins Park and Target Field were their most recent additions to that list.

A matchup between superb right-handers Justin Verlander and Stephen Strasburg can't happen in 2012 now that the latter is shut down for the year, but it could happen in '13 as part of a pair of two-game series between the Tigers and Nationals. The two series take place May 7-8 at Nationals Park and July 30-31 at Comerica Park.

If you are a Subway Series fan, the new scheduling will have a slight effect. The Mets will play four games against the Yankees instead of the usual six, facing their inter-borough rivals twice at Citi Field and twice at Yankee Stadium.

The Dodgers will host the Padres on Monday, April 15, which is Jackie Robinson Day throughout the Majors. The First-Year Player Draft will begin Thursday, June 6. The 84th All-Star Game will be played at Citi Field on July 16, marking the return of the Midsummer Classic to Flushing for the first time since 1964.

The Cardinals will meet up with an old friend from July 2-4: Albert Pujols. That series is in Anaheim, so a trip to Disneyland complete with fireworks and No. 5 might be worth scheduling if you're a Redbirds fan.

After competing in the NL Central since 1994, the Astros won't say goodbye to their former division foes just yet. Houston will play three games in Pittsburgh (May 17-19) and in Chicago against the Cubs (June 21-23), while playing host to the Brewers (June 18-20) and Reds (Sept. 16-18) for three games. They will play a pair of two-game series against the Cardinals that will begin in Houston (June 25-26) before moving to St. Louis (July 9-10).

"We're extremely excited about the 2013 schedule," Astros owner Jim Crane said. "We think our fans will enjoy seeing many of the new teams and players that will be coming to our ballpark next season. This is an exciting time for the Astros organization. We're confident that we're moving in the right direction, both on and off the field. Our plan is in place."

The 12 Monday Opening Day games include Padres at Mets, Marlins at Nationals, Royals at White Sox, Tigers at Twins, Cardinals at D-backs, Mariners at A's, Phillies at Braves, Rockies at Brewers and Cubs at Pirates.

Seven games are scheduled for April 2, and the first full slate of 15 games will be scheduled for Wednesday, April 3.

The regular season will be prefaced by the third edition of the World Baseball Classic, won the first two times by Japan. An expanded field of 28 nations will play at sites around the globe, starting with the first qualifier on Sept. 19 and leading up to the main tournament in March, with dates and ticket availability to be announced later.

"I know I'm going to guarantee the [MLB] managers and the general managers that I'm going to have these guys going back to their teams ready to start the season," said Joe Torre, who will manage the U.S. team. "I think that's the most important thing I can commit to those teams. I'll take care of their players, and hopefully they can trust me on that."